Don't feel that you have to stick to the materials on this list. I just finished testing the Naturalmat Organic Hemp Bed Linen Collection, and I can't stop talking about this miracle material. Hemp combines all the best bits of linen, in terms of breathability and durability, and it's that little bit softer to suit sensitive sleepers. If you're looking for something more luxurious, the Shleep Luxury Merino Wool bedding set could be right up your street. 

A duvet cover encases and protects a duvet. Like an envelope, it has an opening where the comforter or duvet is inserted. Once placed inside, the opening is closed with buttons or occasionally a zipper. Duvet covers are generally very decorative and are available in a wide selection of colors and styles. The duvet cover takes the place of a top sheet in Europe, and some people in the U.S. also use it this way.